This invention relates to supersonic fault detection apparatus capable of simultaneously detecting faults or defects by means of a plurality of supersonic probes and comparing and evaluating the results of the detection by an electronic computer.
Supersonic fault detection test is generally carried out with a single probe, but with such device it is impossible to accurately detect the position and orientation of the fault in an object to be tested. For this reason, in order to precisely determine the distribution of the faults it is necessary to use a number of probes so as to compare and analyze the test results. Furthermore, as the path and attenuation of the supersonic beam differ depending upon the shape and material of the object it is necessary to evaluate the position and size of the fault by taking into consideration the effects of these factors.
However, as the data regarding the result of supersonic fault detection are abundant it is difficult to compare and investigate the data obtained by using a plurality of probes by taking into consideration the material of the object and the characteristic of the probe. According to one example of the method of simultaneously detecting faults by using a plurality of probes, two probes are moved simultaneously along both sides of a portion of the object which is expected to contain faults, for example, a weld seam of a pipe. With this method, however, it is not only impossible to compare the test data of three or more probes but also impossible to separately evaluate defects which extend along the paths of more than two supersonic beams. In such a case, only the largest fault is detected. Where the supersonic beam paths of two probes are different, that is, where the probes have different characteristics and where it is necessary to consider the attenuation of the supersonic wave, it is impossible to correctly evaluate the distribution of the faults.